Saturday, March 31, 2012

Above is the latest severe weather outlook for this afternoon and evening from the Storm Prediction Center (SPC) in Norman, OK. Severe storms are forecast within the yellow shaded area across the middle Mississippi Valley and into the mid-South. Large hail and damaging wind gusts will be the primary threat in this region.

If you live in this area, please remain alert to the possibility of severe weather this afternoon and evening. Listen to NOAA Weather Radio, local media or another trusted source for later statements and possible warnings. Make sure that you've identified the best sheltering option for your location as well.

Elsewhere, several pockets of strong to locally severe storms are possible within the green shaded areas near the "See Text" wording on the image. If you live in these areas, keep in mind that while severe weather will not likely be widespread, some stronger storms could produce hail and/or wind gusts near severe limits this afternoon and evening (mainly before sunset).

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Friday, March 30, 2012

The above video shows a rare sight - a tornado in Mexico. Don't get me wrong... tornadoes are not rare in Mexico, but a video of one certainly is!

This tornado was captured by Melissa Estrada yesterday, March 29, 2012, at approximately 3:30 PM CDT along the Nuevo Laredo-Monterrey Highway, reportedly between kilometer markers 68 and 70.

Note an overturned truck in the center median at about 3:05 into the video. The truck was presumably hit by the tornado, or some other sort of thunderstorm outflow turned it over.

This is a nice video showing most of the structure of the tornado. She also very wisely came to a complete stop when she got too close, then resumed her travels after the tornado had safely crossed the road (unlike the truck, apparently).

This same complex of thunderstorms later produced very large hail across a widespread area deep in the valley of South Texas on Thursday evening. Golfball to baseball sized hail caused extensive damage in the McAllen and Mission areas. The hail accumulated up to 6 inches deep in some places:

Photo courtesy Gabe Hernandez/The Monitor

McAllen Area Starbucks Battered by HailPhoto Courtesy NWS Brownsville

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The above visible satellite picture was taken just a few moments ago. I have drawn the location of the surface dryline in yellow. To the West of the boundary, the temperature has risen into the mid 90s over southwest Texas, with dew point temperatures only in the single digits or teens (further signifying the very dry air that is in place behind the boundary). To the East of the dryline, dew point temperatures are in the 50s and 60s.

The strong difference in moisture profile across the boundary is leading to convergence, which may allow for thunderstorm development over the next few hours along and ahead of the boundary. You can see a large field of cumulus clouds bubbling up ahead of the boundary over southwestern Oklahoma, and if you look closely, you can also see a small line of towering clouds beginning to develop along the dryline to the southwest of Brownwood, Texas.

If thunderstorms are able to develop along and ahead of the dryline late this afternoon or this evening, very large hail will be likely, as shown within the yellow and black hatched area on the image below:

The main limiting factor at this time is the presence of a strong capping inversion across the region. The convergence will have to become strong enough along the dryline in order for a thunderstorm to break through the cap, develop and become severe. It is possible that some weak energy in the upper atmosphere may also over over this region late this afternoon or early this evening and assist in a few storms breaking the cap as well.

Folks living within the yellow shaded and black hatched area on the above image should remain alert to any thunderstorm development later today. While the probability of a storm developing is not necessarily high, any storm that does form will almost certainly become severe due to the high amount of instability that is in place across this region.

Elsewhere, severe thunderstorms are currently developing (as we had expected in the morning outlook) over the Midwest and Ohio Valley, where a couple of Severe Thunderstorm Watches are already in effect.

If you live in any of the above mentioned areas, please remain on the alert this afternoon and into this evening. Review your severe weather safety tips and be sure to identify the best sheltering option for you and your family at home, work or school.

Are you new to the blog? Welcome! Please click on the icons below to "Like" my facebook page and/or follow me on twitter. You'll find posts at these locations that aren't always on the blog, especially during rapidly changing weather situations...

New to the blog? Welcome! Please click on the icons below to "Like" my facebook page and/or follow me on twitter. You'll find posts at these locations that aren't always on the blog, especially during rapidly changing weather situations...

Severe thunderstorms are forecast within two areas today, as noted in yellow on the above image.

The first, and at least initially the most pronounced, is likely to be over portions of the Midwest and Ohio valley region. A moist, unstable airmass is in place and will interact with an upper-level weather disturbance to initiate thunderstorm development by mid to late afternoon, likely near the Western edge of the severe weather outlook area initially.

Once developed, this activity will move and/or develop to the East over the Ohio Valley region into this evening.

Large hail and damaging winds are the primary threats in this region, however a few tornadoes cannot be ruled out with any particularly well organized, and especially isolated, storms.

Further West and Southwest, a "conditional" risk of severe weather exists over portions of the southern Plains for late this afternoon into this evening. The atmosphere over this region will become very unstable by this afternoon, along and South of a weak boundary along the Kansas/Oklahoma border, and along and East of a surfacedryline.

The most likely form of severe weather in this region will be the potential for very large (2 inch diameter or greater) hail, as shown by the yellow shaded and black hatched area on the image below:

I point out that the risk of severe weather is "conditional" for two reasons: (1). the atmosphere over much of this region, especially in southern Oklahoma and Texas, is "capped" and (2). while there will be at least some weak upper-level support to help break the cap, the timing and exact location of that support is in question at this time.

If thunderstorms are able to form in this region, they will likely become severe. The most likely time for this to take place would be late this afternoon into this evening. I will continue to monitor incoming data and will provide an update on the Southern Plains as the situation becomes more clear during the day today...

If you live in either of the severe weather threat areas for today, please remain on the alert. Review your severe weather safety tips and be sure to identify the best sheltering option for you and your family at home, work or school.

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Thursday, March 29, 2012

Above is the severe weather outlook for today from the Storm Prediction Center in Norman, OK. Severe thunderstorms are forecast within the yellow shaded area on the image.

As was the case yesterday, a moist, unstable airmass is in place near weak surface boundaries in the central and part of the southern Plains. One or more upper level disturbances will move across this region during the afternoon and evening, resulting in thunderstorm development, some of which will be severe.

Large hail (some greater than 2 inches in diameter) and damaging winds are likely with any severe storms that form in this region. An isolated tornado or two is also possible.

The greatest risk of very large hail will reside within the red and black hatched area on the image below:

The enhanced risk of very large hail includes the Kansas City Metro area, as well as the cities of Topeka, Manhattan, Lawrence and Emporia.

Most of the vigorous thunderstorm development will take place from mid to late afternoon into this evening. With low-level instability and upper-level energy stronger today than yesterday, the severe storms are likely to be more numerous this afternoon and evening as compared to yesterday.

Elsewhere, isolated severe thunderstorm development is possible Southward along the dryline from southcentral Kansas into northwestern Oklahoma, and perhaps parts of West Texas. This would mainly be from late afternoon into the mid-evening hours, with large hail and damaging wind gusts the primary threat in this region.

If you live in the severe weather threat areas for today, please remain on the alert. Review your severe weather safety tips and be sure to identify the best sheltering option for you and your family at home, work or school.

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Wednesday, March 28, 2012

As expected, thunderstorms are developing along a frontal boundary extending from southern Indiana, Eastward into the state of Maryland at early afternoon (as shown on the radar image above). A Severe Thunderstorm Watch was recently issued for this general region, valid until 9pm EDT:

Large hail and strong, gusty winds are the primary hazards that will be associated with this activity. The storms themselves will generally move toward the East as the line gradually sags to the South during the afternoon and early evening hours.

Further West, thunderstorms are likely to develop over portions of central and eastern Kansas by mid to late afternoon, within the yellow and red shaded, black hatched area on the image below:

The atmosphere over this region is becoming increasingly unstable, and a Northward moving warm front will provide additional lifting. Also, a weak disturbance in the upper-atmosphere will provide for focus for development in this area.

Very large hail, damaging wind gusts and a few tornadoes are possible in this region.

This activity will likely develop into a cluster or small complex of thunderstorm activity and move Eastward into adjacent portions of west-central or southwestern Missouri late this evening or early tonight.

Elsewhere, and further to the Southwest, isolated thunderstorms may develop along a surface dryline from southwest Texas into the eastern Texas panhandle region late this afternoon or early this evening (as indicated by that part of the brown shaded area on the image above). This activity will be isolated, but any organized storm in this region could produce large hail and strong, gusty winds.

If you live across any of the severe weather threat areas described above, please remain alert. Listen to NOAA Weather Radio, local media or another trusted source for the latest information, watches and possible warnings. Take a few moments to review severe weather safety and preparedness tips and be ready to seek shelter if threatening weather is observed or a warning is issued for your area.

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There are several pockets along a swath extending from the Plains into the Mississippi, Tennessee, Ohio Valley region and into the northeast where strong to severe storms will threaten today. This is not a situation where particularly widespread severe weather is likely (except perhaps with respect to hail in Kansas, which we'll discuss in a moment), but rather scattered pockets of locally severe weather are possible in several areas.

In general, strong to locally severe storms are possible today within the brown shaded areas on the above image from the Storm Prediction Center (SPC). The greatest chance of severe weather lies within the yellow shaded areas on the same image.

Large hail and damaging thunderstorm wind gusts are the primary severe weather threats in these areas today, however an isolated tornado cannot be completely ruled out.

The main threat of severe weather will occur this afternoon and into this evening as thunderstorms develop and/or increase during afternoon heating along and to the South of a surface frontal boundary. This development will be enhanced by several weak upper-level disturbances that are forecast to move across the primary severe weather threat areas in yellow.

If there were to be one area that is likely to experience the most organized and/or widespread severe weather, it would be within the yellow and black hatched area on the image below, extending from central Kansas into southwest Missouri:

Within this region, there will be a threat of particularly large hail (i.e., 2 inches in diameter or larger will be possible). This threat will begin during the afternoon hours, and damaging wind gusts may also become a pronounced threat in this region by this evening.

Elsewhere, throughout the remaining severe weather outlook areas, severe weather will be possible on at least a scattered basis, with large hail and strong wind gusts the primary threats this afternoon into this evening. Within the brown shaded areas on the above image, the threat of severe weather will mainly take place on an isolated basis this afternoon or evening, as thunderstorms are expected to be less organized in these areas.

If you live across any of the severe weather threat areas for today, please remain alert. Listen to NOAA Weather Radio, local media or another trusted source for the latest information, watches and possible warnings. Take a few moments to review severe weather safety and preparedness tips and be ready to seek shelter if threatening weather is observed or a warning is issued for your area.

Check back for an updated outlook by mid to late morning. We'll try to become even more specific as to the severe weather threats in that update...

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Tuesday, March 27, 2012

Above is the Severe Weather Outlook for today and tonight from the Storm Prediction Center (SPC) in Norman, OK. Severe storms are forecast within the yellow shaded area on the image.

Large hail and damaging wind gusts will be the primary severe weather threats later today, although an isolated tornado cannot be completely ruled out from any storm that is able to become well organized (this would be a very isolated situation, however).

A cold front is expected to be located along the Northwest edge of the severe weather risk area by early evening, from northwest Missouri into northwest Illinois. At the same time, a weak disturbance in the upper atmosphere will approach from the West, resulting in isolated to scattered thunderstorm development along and ahead of the frontal boundary.

At this time it appears that thunderstorms aren't likely to develop in this region until this evening, after 6 or 7pm CDT.

Elsewhere, back to the West and Southwest, the above mentioned cold/cool front will stretch into southwestern Kansas by late afternoon, where it will intersect with a dryline that will extend Southward into the Oklahoma/Texas panhandle region and into southwest Texas.

There will be a chance for isolated strong to severe thunderstorm development along these boundaries (and particularly the dryline in southwest Texas) late this afternoon into this evening (see the green shaded area on the above image with the wording "See Text").

Though very isolated, any storm that forms in this region could become severe with large hail the main threat.

If you live across the severe weather threat area for later today, please remain alert. Listen to NOAA Weather Radio, local media or another trusted source for the latest information, watches and possible warnings. Take a few moments to review severe weather safety and preparedness tips and be ready to seek shelter if threatening weather is observed or a warning is issued for your area.

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When watches are in effect, you can click on the map to obtain details on a specific watch area. As shown in the example below, after you've selected a specific watch area on the SPC's Watch page, you can click on "Counties" (as shown within the red circle) and view the counties that are included in the watch, as well as the valid time, etc.:

I hope that you'll find the information useful, especially since it is updated in real time.

Now that we've dedicated a permanent location on the blog to the latest severe weather watch information, going forward you probably won't see me make individual posts regarding the issuance of a watch (like this one). I still may do so in special situations, but not on a regular basis. That way I'll be able to focus more on letting you know what is about to happen before a watch is issued, and what is taking place once the watch is in effect.

You may have also noticed that the "twitter widget" has been spruced-up a bit as well. It is also located on the right hand side of the page, just after the "About Me" box:

Several more changes/new features are coming up soon, including an exclusive offer that I hope you'll both enjoy and find useful. Be sure to check back throughout the week for updates!

Are you new to the blog? Welcome! Please click on the icons below to "Like" my facebook page and/or follow me on twitter. You'll find posts at these locations that aren't always on the blog, especially during rapidly changing weather situations...

Above is the latest severe weather outlook for today from the Storm Prediction Center (SPC) in Norman, OK. Severe thunderstorms are possible within the yellow shaded area over the Dakotas and extreme western Minnesota, mainly from late this afternoon and evening.

At least scattered thunderstorms are forecast to develop over this region by late afternoon and into this evening as a surface low pressure center and cold front combine with energy from an upper-level weather disturbance.

Large hail and damaging wind gusts are the primary threats, however isolated tornado development also cannot be ruled out.

Further South, in West Texas and along the Texas/New Mexico border, isolated thunderstorms may form late this afternoon along a developing surface dryline. There will not be support for widespread development, however any storm that does form could produce large hail and strong, gusty winds. Any such development is likely to dissipate by sunset.

If you live in or near the severe weather threat areas mentioned above, please be on the lookout for changing weather conditions later today. Listen to NOAA Weather Radio, local media, or another trusted source for later information, watches and possible warnings. Make sure that you identify your best sheltering option at home, work or school, and be prepared to go there if threatening weather is observed or a warning is issued.

Sunday, March 25, 2012

Scattered strong to severe thunderstorms are forecast across eastern North Carolina later this afternoon and into this evening, as the atmosphere heats-up beneath an upper-level low pressure system. The primary risk of severe weather is shown by the yellow shaded area on the above image.

Large hail and strong, gusty winds will be the primary severe weather threats, however an isolated tornado cannot be ruled out due to the presence of turning associated with the upper-level low pressure system.

Elsewhere, later tonight, there will also be a threat of isolated thunderstorms with hail to near severe limits over parts of the Dakotas and northern Nebraska, as shown by the wording "See Text" on the above image. Isolated to widely scattered thunderstorms are forecast to develop across this region after 10pm or Midnight tonight, some of which could become strong enough to produce hail.

The main threat of hail near severe limits over South Dakota and northeast Nebraska will be within the brown shaded area on the above image. Again, this will not be a widespread threat, but rather isolated.

Those living in the severe weather threat areas for this afternoon and evening over North Carolina should remain alert today. Listen to NOAA Weather Radio, local media, or another trusted source for later information, watches and possible warnings. Make sure that you identify your best sheltering option at home, work or school, and be prepared to go there if threatening weather is observed or a warning is issued.

Saturday, March 24, 2012

The above Severe Thunderstorm Watch has been issued by the SPC in Norman OK and is valid until 2am EDT. The severe thunderstorm watch includes the cities of Beaufort, Charleston, Columbia, Myrtle Beach and Florence.

Severe thunderstorms with large hail and damaging wind gusts are the primary threat in this area. An isolated tornado cannot be ruled out.

If you live in these areas, please remain alert today. Identify your sheltering location and be prepared to move there quickly if threatening weather is observed or a warning is issued.

The above Tornado Watch was just issued by the Storm Prediction Center (SPC) in Norman, OK. It is valid until Midnight EDT and includes the cities of Lynchburg, Danville and Richmond.

Severe thunderstorms capable of producing tornadoes, large hail and damaging wind gusts are possible in and close to the watch area.

If you live in these areas, please remain alert this afternoon and evening. Identify your sheltering location and be prepared to move there quickly if threatening weather is observed or a warning is issued.

The above Tornado Watch was just issued by the Storm Prediction Center (SPC) in Norman, OK. It is valid until 11pm EDT and includes the cities of Raleigh-Durham, Danville, Lynchburg, Winston-Salem and Fayetteville.

This Tornado Watch replaces that part of the Severe Thunderstorm Watch that was issued early for much of the same area.

Severe thunderstorms capable of producing tornadoes, large hail and damaging wind gusts are possible in and close to the watch area.

If you live in these areas, please remain alert this afternoon and evening. Identify your sheltering location and be prepared to move there quickly if threatening weather is observed or a warning is issued.

The above Severe Thunderstorm Watch has been issued by the SPC in Norman OK and is valid until 10pm EDT. The severe thunderstorm watch includes the cities of Elkins, Charlottesville and Beckley.

Thunderstorms are forecast to increase in number and intensity (generally from West to East) across the watch area this afternoon and evening. Some of the storms are likely to become severe with large hail and damaging wind gusts the primary threat. An isolated tornado or two also cannot be ruled out.

If you live in these areas, please remain alert today. Identify your sheltering location and be prepared to move there quickly if threatening weather is observed or a warning is issued.